使用環形緩衝區取得 Always On 可用性群組的健全狀況資訊

發行項
05/04/2023

適用於：SQL Server

某些診斷的 Always On 可用性群組 (AG) 資訊可從 SQL Server 通道緩衝區，或是 sys.dm_os_ring_buffers 動態管理檢視 (DMV) 取得。信號緩衝區在 SQL Server 啟動期間建立，並針對內部診斷記錄 SQL Server 系統中的警示。其不受支援，但您仍然可以在針對問題進行疑難排解時，從它們擷取有用的資訊。這些信號緩衝區在 SQL Server 當機或損毀時，提供診斷的其他資源。

以下 Transact-SQL (T-SQL) 查詢從 AG 通道緩衝區擷取所有事件記錄。

SELECT * FROM sys.dm_os_ring_buffers WHERE ring_buffer_type LIKE '%HADR%'

若要讓資料更容易管理，請依日期和信號緩衝區類型來篩選資料。以下查詢會從今天出現的指定信號緩衝區擷取記錄。

DECLARE @start_of_today DATETIME,
    @start_of_tomorrow DATETIME;

SET @start_of_today = CAST(FLOOR(CAST(GETDATE() AS FLOAT)) AS DATETIME);
SET @start_of_tomorrow = DATEADD(DAY, 1, @start_of_today);

DECLARE @runtime DATETIME;

SET @runtime = GETDATE();

SELECT CONVERT(VARCHAR(30), @runtime, 121) AS data_collection_runtime,
    DATEADD(ms, - 1 * (inf.ms_ticks - ring.timestamp), GETDATE()) AS ring_buffer_record_time,
    ring.timestamp AS record_timestamp,
    inf.ms_ticks AS cur_timestamp,
    ring.*
FROM sys.dm_os_ring_buffers ring
CROSS JOIN sys.dm_os_sys_info inf
WHERE ring_buffer_type = '<RING_BUFFER_TYPE>'
    AND DATEADD(ms, - 1 * (inf.ms_ticks - ring.timestamp), GETDATE()) >= @start_of_today
    AND DATEADD(ms, - 1 * (inf.ms_ticks - ring.timestamp), GETDATE()) < @start_of_tomorrow;
GO

每個記錄中的 record 資料行都包含 XML 格式的診斷資料。不同的信號緩衝區類型有不同的 XML 資料。如需每個通道緩衝區類型的詳細資訊，請參閱可用性群組通道緩衝區類型。若要讓 XML 資料更易於閱讀，您需要自訂您的 T-SQL 查詢以擷取所需的 XML 元素。例如，以下查詢會從 RING_BUFFER_HADRDBMGR_API 信號緩衝區擷取所有事件，並將 XML 資料格式化為個別的資料表資料行。

WITH hadr (ts, type, record)
AS (
    SELECT timestamp AS ts,
        ring_buffer_type AS type,
        CAST(record AS XML) AS record
    FROM sys.dm_os_ring_buffers
    WHERE ring_buffer_type = 'RING_BUFFER_HADRDBMGR_API'
    )
SELECT ts,
    type,
    record.value('(./Record/@id)[1]', 'bigint') AS [Record ID],
    record.value('(./Record/@time)[1]', 'bigint') AS [Time],
    record.value('(./Record/HadrDbMgrAPI/dbId)[1]', 'bigint') AS [DBID],
    record.value('(/Record/HadrDbMgrAPI/API)[1]', 'varchar(50)') AS [API],
    record.value('(/Record/HadrDbMgrAPI/Action)[1]', 'varchar(50)') AS [Action],
    record.value('(/Record/HadrDbMgrAPI/role)[1]', 'int') AS [Role],
    record.value('(/Record/Stack)[1]', 'varchar(100)') AS [Call Stack]
FROM hadr
ORDER BY record.value('(./Record/@time)[1]', 'bigint') DESC;
GO

可用性群組通道緩衝區類型

sys.dm_os_ring_buffers 中有四個 AG 通道緩衝區。下節描述通道緩衝區類型和每個通道緩衝區類型的 record 資料行內容的範例。

RING_BUFFER_HADRDBMGR_API

記錄已發生或正在發生的狀態轉換。查看狀態轉換時，請特別注意 objectType 值。

<Record id="11" type="RING_BUFFER_HADRDBMGR_STATE" time="860243">
  <HadrDbMgrState>
    <objectType>HadrUsers</objectType>
    <currentState>HDbMState_Starting</currentState>
    <proposedState>HDbMState_Started</proposedState>
    <targetState>HDbMState_Started</targetState>
    <legalTransition>Y</legalTransition>
    <role>1</role>
  </HadrDbMgrState>
</Record>

RING_BUFFER_HADRDBMGR_STATE

記錄 AG 活動所建立的內部方法或函式呼叫。它可以顯示暫止、繼續或角色變更等資訊，且包括進入和離開點。

<Record id="45" type="RING_BUFFER_HADRDBMGR_STATE" time="1723487912">
  <HadrDbMgrState>
    <dbId>5</dbId>
    <objectType>HadrDbMgr</objectType>
    <currentState>HDbMState_Starting</currentState>
    <proposedState>HDbMState_Started</proposedState>
    <targetState>HDbMState_Started</targetState>
    <legalTransition>Y</legalTransition>
    <role>2</role>
  </HadrDbMgrState>
</Record>

RING_BUFFER_HADRDBMGR_COMMIT

<Record id="0" type="RING_BUFFER_HADRDBMGR_COMMIT" time="1723475368">
  <HadrDbMgrCommitPolicy>
    <dbId>5</dbId>
    <replicaId>883a18f5-97d5-450f-8f8f-9983a4fa5299</replicaId>
    <dbHardenPolicy>KillAll</dbHardenPolicy>
    <dbSyncConfig>0x0</dbSyncConfig>
    <syncPartnerCount>0</syncPartnerCount>
    <minSyncPartnerConfig>0</minSyncPartnerConfig>
    <partnerHardenPolicy>KillAll</partnerHardenPolicy>
    <partnerSyncConfig>0x0</partnerSyncConfig>
    <logBlock>0x0000000000000000</logBlock>
    <leaseExpired>Y</leaseExpired>
    <partnerChange>N</partnerChange>
    <role>2</role>
  </HadrDbMgrCommitPolicy>
</Record>

RING_BUFFER_HADR_TRANSPORT_STATE

<Record id="3" type="RING_BUFFER_HADR_TRANSPORT_STATE" time="1723485399">
  <HadrTransportState>
    <agId>08264B79-D10B-412F-B38D-CA07B08E9BD8</agId>
    <localArId>883A18F5-97D5-450F-8F8F-9983A4FA5299</localArId>
    <targetArId>628D6349-72DD-4D18-A6E1-1272645660BA</targetArId>
    <currentState>HadrSession_Configuring</currentState>
    <targetState>HadrSession_Connected</targetState>
    <legalTransition>Y</legalTransition>
  </HadrTransportState>
</Record>

從信號緩衝區剖析 XML 資料

您可以在查詢中使用 value() 方法 (xml 資料類型)，剖析正在檢查的通道緩衝區的 Record 欄位。若要使用這個方法，您必須先使用 CAST 將信號緩衝區中的記錄資料行轉換成 XML。例如，以下查詢示範如何使用此方法將 RING_BUFFER_HADRDBMGR_API 剖析成可讀取的格式。

WITH hadr (ts, type, record)
AS (
    SELECT timestamp AS ts,
        ring_buffer_type AS type,
        CAST(record AS XML) AS record
    FROM sys.dm_os_ring_buffers
    WHERE ring_buffer_type = 'RING_BUFFER_HADRDBMGR_API'
    )
SELECT ts,
    type,
    record.value('(./Record/@id)[1]', 'bigint') AS [Record id],
    record.value('(./Record/@time)[1]', 'bigint') AS [Time],
    record.value('(./Record/HadrDbMgrAPI/dbId)[1]', 'bigint') AS [dbid],
    record.value('(/Record/HadrDbMgrAPI/API)[1]', 'varchar(50)') AS [API],
    record.value('(/Record/HadrDbMgrAPI/Action)[1]', 'varchar(50)') AS [Action],
    record.value('(/Record/HadrDbMgrAPI/role)[1]', 'int') AS [Role],
    record.value('(/Record/Stack)[1]', 'varchar(100)') AS [Call Stack]
FROM hadr
ORDER BY record.value('(./Record/@time)[1]', 'bigint') DESC;
GO

共用方式為